System and method for controlling voltage on a distribution feeder

Abstract

A system for controlling voltage on a distribution feeder includes a plurality of capacitor banks that can be connected to or disconnected from the distribution feeder. A first bank is configured to connect to the distribution feeder when a first voltage is below a first lower threshold value and to connect to the distribution feeder when the first voltage is above a first upper threshold value. The first upper threshold and first lower threshold are determined based off an operational set point. The system further includes a sensor configured to measure the first voltage and a controller in operable communication with the plurality of capacitor banks configured to determine the operational state of the first and second capacitor banks and, based on the first voltage, send a first instruction to the first capacitor bank, the first instruction causing the capacitor bank to vary the operational set point.

The invention claimed is: 
     
       1. A method for controlling voltage on a distribution feeder, the distribution feeder including a plurality of capacitor banks associated with the distribution feeder, the plurality of capacitor banks including a first capacitor bank and a second capacitor bank, the first capacitor bank being configured to connect to the distribution feeder when a first voltage is below a first lower threshold value and to disconnect from the distribution feeder when the first voltage is above a first upper threshold value, the first upper threshold value and first lower threshold value being determined based on an operational set point of the first capacitor bank, the method comprising:
 determining at a computing device the operational state of the first and second capacitor banks; 
 measuring the first voltage with a voltage sensor associated with the first capacitor bank; 
 determining whether the first capacitor bank should be connected to or disconnected from the distribution feeder; and 
 sending a first instruction to the first capacitor bank, the first instruction causing the first capacitor bank to vary its operational set point. 
 
     
     
       2. The method of  claim 1 , wherein the operational state is one of connected or not connected. 
     
     
       3. The method of  claim 2 , wherein determining whether the first capacitor bank should be connected to or disconnected from the distribution feeder includes:
 determining that operational state is connected; and 
 determining that disconnecting the first capacitor bank will flatten a voltage profile of the distribution feeder. 
 
     
     
       4. The method of  claim 3 , sending includes sending the first instruction such that it causes the first capacitor bank to increase its operational set point. 
     
     
       5. The method of  claim 2 , wherein determining whether the first capacitor bank should be connected to or disconnected from the distribution feeder includes:
 determining that operational state is disconnected; and 
 determining that connecting the first capacitor bank will flatten a voltage profile of the distribution feeder. 
 
     
     
       6. The method of  claim 5 , wherein sending includes sending the first instruction such that it causes the first capacitor bank to decrease its operational set point. 
     
     
       7. The method of  claim 1 , further comprising:
 after sending the first instruction to the first capacitor bank to cause it to vary its operational set point, sending a hold instruction to one or more of the plurality of capacitor banks that disallows them from changing operational status; 
 determining a lower input voltage for the distribution feeder; and 
 sending a second instruction to the first capacitor bank to decrease its operational set point. 
 
     
     
       8. The method of  claim 7 , wherein the lower input voltage is between 126 and 114 volts. 
     
     
       9. The method of  claim 7 , wherein the lower input voltage is lower than a current input voltage by a voltage difference and the second instruction causes the first capacitor bank to lower its operational set point in an amount equal to the voltage difference. 
     
     
       10. The method of  claim 7 , further comprising:
 sending a release instruction to the one or more of the plurality of capacitor banks that allows them to change operational status. 
 
     
     
       11. A system for controlling voltage on a distribution feeder, the system comprising:
 a plurality of capacitor banks that can be connected to or disconnected from the distribution feeder, the plurality of capacitor banks including a first capacitor bank and a second capacitor bank, the first capacitor bank being configured to connect to the distribution feeder when a first voltage is below a first lower threshold value and to disconnect from the distribution feeder when the first voltage is above a first upper threshold value, the first upper threshold and first lower threshold being determined based on an operational set point; 
 a sensor configured to measure the first voltage; and 
 a controller in operable communication with the plurality of capacitor banks configured to determine the operational state of the first and second capacitor banks and, based on the first voltage, send a first instruction to the first capacitor bank, the first instruction causing the capacitor bank to vary the operational set point. 
 
     
     
       12. The system of  claim 11 , wherein the controller is configured to determine whether the first capacitor bank should be connected to or disconnected from the distribution feeder based on a determination that an operational state of the first capacitor bank is connected and a determination that disconnecting the first capacitor bank will flatten a voltage profile of the distribution feeder. 
     
     
       13. The system of  claim 12 , wherein the controller is configured to send the first instruction such that it causes first the capacitor bank to increase the operational set point. 
     
     
       14. The system of  claim 11 , wherein the controller is configured to determine whether the first capacitor bank should be connected to or disconnected from the distribution feeder based on a determination that an operational state of the first capacitor bank is disconnected and a determination that connecting the first capacitor bank will flatten a voltage profile of the distribution feeder. 
     
     
       15. The system of  claim 14 , wherein the controller is configured to send the first instruction such that it causes first the capacitor bank to decrease the operational set point.